Automatic choke valve



April 11, 1939 J. E. ESHBAUGH AUTOMATIC CHOKE VALVE 2 Sheets-Sheet l Filed Nov. 24, 1934 .Ulm-....2

an #y April 11, 1939- J. E. ESHBAUGH 2,154,086

AUTOMATIC @HOKE VALVE Filed Nov. 24, 1954 2 Sheets-Sheet 2 fyi/"g5 Patented Apr. 11, 1939 2,154,086

UNITED STATES PATENT OFFICE AUTOMATIC CHOKE VALVE Jesse E. Eshbaugh, Flint, Mich., assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 24, 1934, Serial No. 754,591 8 Claims. (Cl. 2261-39) 'I'his invention relates to mechanisms for reg- I3 to which an operating arm I4 is secured and ulating the ratio of fuel to air in the combustible a butterfly choke Valve l5 which is mounted cifmixture supplied by the carburetor to the cylcenter on a shaft I6 so that the flow of air into inders of an internal combustion engine when its the carburetor will tend to open it.

P temperature is below that at which it is designed To the intake manifold ll adjacent the car- 5 l to operate. buretor l0, there is secured by means of screws r The mechanism in which this invention resides l1 a hollow body I8 which is divided into upper y effects the desired regulation by controlling the and lower compartments by a partition I9. In position of the choke valve of the carburetor of the upper compartment, there is located a metal lo the engine in accordance with engine operating bellows 2U to whose open upper end there is se- 10 conditions. The mechanism is so designed that, cured a flange 22 whoseouter edge is seated on if the engine is cranked when its temperature is the upper end f the bOdY and clamped between below a predetermined value, it will, until the it and the outer edge of an inverted cup-shaped engine begins to operate under its own power and Cover 23 by SCreWS 24. The lower end 0f the 5 for a short time thereafter, be supplied with a bellows 2U is closed by a head 2l to which there 15 super-rich combustible mixture, that, thereis secured a rod 44 which projects into the lower after, until the temperature. er the engine excompartment of the body I8 through an opening ceeds a predetermined value, it will be supplied ln the partition I9. Expansion of the bellows with a combustible mixture whose richness varies iS limited by the partition i9 and @OntraetiOn inversely with the temperature and speed of the thereof is limited by a rod which depends from 20 2O engine and that, if, during the period under conthe COVer 23.

sideration, the engine tends to stall or the throt- The interOl 0f the bellows 20 communicates tle valve of the carburetor is moved toward its With the interior 0f the intake manifold ,Il open position, there will be a momentary increase through a transverse bore 26 in the side wall of 25 in the richness of the combustible mixture supthe Cover 23 and a Vertical bore 2T which extends 25 plied to the engine which will prevent stalling through the upper Weil1 0f the intake manifold Il, of the engine or insure smooth and rapid accelerthe Wall 0f the bOdY i3 and iIltO the @Over 23. ation, In the lower enlarged end of the portion of the For a better understanding of the nature and bore 21 which is located in the body i8, there is 30 objects of the present invention, reference is SCIeWed a Plug-like element 23if1t0 WhOSe upper 30 made to the following specification wherein there surface there extends a cylindrical recess 29 is described the preferred embodiment of the inwhich is encircled by a cylindrical flange 30. vention which is illustrated in the accompanying Frm the lOWei Side 0f the plug-like element 28 drawings. a relatively small bore 32 extends into the recess In the accompanying drawings: 29. To the cylindrical flange 30, there is secured 35 Figure 1 shows, ln elevation, mechanism in a combined valve cage and guide 33 within which which my invention is embodied installed on an there is located a poppet `valve 34 which is norinternal combustion engine, mally seated on the upper end of the flange by Figure 2 is a section through the mechanism gravity and a light Spring 35. ThIOllgh the Centaken on the line 2--2 of Figure'. ter of the valve 34, there extends a bore 36 into o 40 Figure 3 ls an enlarged view of the valve unit which there projects a pin 31 which 1s of slightly which is incorporated in the mechanism smaller diameter than the bore 36. The pin 31 Figure 4 is a section taken on the line 4 4 of is loosely connected to the upper end of the com- Figure 2. bined valve cage and guide 33 so that it may Figure 5 is a section taken on the line 5-5 of flutter during OperetiOn 0f the engine and dlS- 4,5 Figure 4. lodge any particles of foreign matter which may Figure 6 is a fragmentary view taken as indifind their way into the small opening between cated by the arrows 6--6 of Figure 4. it and the bore`33.

Figure 'I is a perspective view of two of the ele- To the side of the body i8 which is nearest the. ments of the mechanism. exhaust manifold 38 0f the engine, there is se- 50 In the drawings, the reference l0 indicates a cured a bearing 39 whose inner end extends into carburetor which is connected to the cylinders of the lower compartment 0f the bOdY- On eaIS an internal combustion engine by a manifold Il. which are formed on an intermediate portion of In the carburetor lll, there is included a butterthe bearing, there is seated a cup-shaped housing fly throttle valve l2 which is mounted on a shaft 40 whose open end is located adjacent the ex- 55 the screws 4i which extend through the earsmust manifold n and into whose interior :ne outer end of the bearing 3! extends. The cupshaped housing 40 is secured to the body i8 by on the bearing Il and secure the latter to the body. j

In the bearing Il,

through and is iournaled inthe hollow shaft 42vv and the wall of the housing l5 opposite that through which the bearing nextends. To the end of the shaft 45 which extends through the wall of the body Il opposite thatftlirough which the bearing I9 extends, there is secured an arm 46 whose outer end is pivotallyconnected to one end of a rod 41. The opposite end of the rod 41 is pivotally connected to the outer end of an arml 4B which is secured to the shaft l5 on which the I chokevalve I5 is mounted. l

To the end of the hollow shaft 42 which is located within the cup-shaped housing 40, there is secured a sector 40 in which there is provided an arcuate slot 50 in which a pin 5| is adjustably secured. To the end of the shaft 45 which is located within the cup-shaped housing 40, there is secured the inner end of a bimetalllc coil spring 52 whose outer end engages the pin 5I. when'its` temperature is below a predetermined value. f l' To the shaft 45. between-,theinner end'oi' the 5 i hollow shaft 42 and the wall ofthe body i8 posite that through wl'liehtheV hollow 'shaft' extends, there is secured an element 53.l l Theeles ment 53 is a U-shaped piece of' sheetfmejtalyl through whose arms the shaft 45 extends and extends the screw 58 which secures the element K i to the shaft 45. On each of the arms of theelement 53, there is formed a finger. 'The finger 59 overlies the finger 51 Von the arm 43 and the linger 54 is adapted to engage the abutment 55 to limit movement of thechoke valve l5 toward its closed position and to engage the abutment 55 to limit movement of the choke valve toward its open position. i

When an engine onwhichgthere is installed the mechanism illustrated in th drawings and hereinbefore described is not operating, the choke valve l5 is, unless e temperature of the engine exceeds a predetermined value, held closed by the bimetalllc coil spring 52. If, when its temperature is below this predetermined value, the engine is cranked, the choke valve l 5 will remain closed or very nearly closed until the engine begins to operate under its own power and, consequently, during this period, the engine will be supplied with the extremely rich combustible mixture which is conducive to quick and easy starting. As soon as the engine begins to operate under its' own power, the flow of air past the choke valve I5l will cause it to open partially and the ratio of fuel to air in the combustible mixture supplied to the engine will be decreased. 'I'he extent to which the choke valve opens when the engine begins to operate under its own power is dependent upon the speed. of the engine and the resistance offered by the bimetallic coll spring 52 which varies inversely with the temperature of the engine, and the combustible mixture supthere is iournaled a hollow shaft 42 to whose inner lend there is secured an nascose plied to the engine at this time is, although leaner than it was before the engine began to operatev under its own power, very rich.'

As soon as the engine begins to operate under its own power, withdrawal of air from the interior d of the bellows 20 into the intake manifold i I and,

consequently, collapse of the bellows commences. However, because all of the air withdrawn from `the bellows must pass through the small opening between the pin 3l and the bore 36 in the valve 24, an appreciable interval of time, e. g., approximately` nine (9) seconds, elapses before the bel- `lows iscompletely collapsed, l. e., until the head 2| of the bellows engages the lower end of the rod 25. As the bellowsk is collapsed, the rod 44 is a raised and the arm u and the houow shaft 42 are rotated -in a clockwise direction when viewed ther toward its open position and eilects a reduction in the richness of the combustible mixture supplied to the engine without any change in the temperature of the engine. When the head of the bellows 20 approaches the upper v.limit of its mnvement,'the rotation of the arm 43 brings the `finger 51 into engagement with the finger 59 on After the finger 51 engages the the element 53. nger 59, further upward movement of the head of'V the bellows is positively transmitted to the Ichoke valve and, consequently, by the time that ...the bellows is completely collapsed the choke 'valve will be positively opened sufllcientiy to infsure that the combustible mixture supplied to the engine will not be richer than it should during ,jidleoperation of the engine. through whose base which is madeof doublev thickness by folding the sheet metal uponfitself-f What is said in the two sentences next preceding this is, of' course,

4based on the assumption that the choke valve l5 has not, before the finger 5l reaches the upper `limit of its movement, been opened to such an extent that the finger 59 has been moved beyond the upper limit of the path of the finger 51. Of course, if by the time that the head of the bellows reaches the upper limit of its movement, the choke valve has been opened to this extent, it is not desirable that the described action occur and it will not occur.

Because of its proximity to the exhaust manifold 58, the bimetalllc coil spring 52 becomes heated during operation of the engine. Increase in the temperature of the bimetalllc coil spring 52 causes the end thereof which engages the pin 5I to exert increasingly less pressure thereon and,

consequently, as the temperature of the enginev increases the bimetalllc coil spring offers less and less resistance to movement of the choke valve I5 toward its open position. Therefore, the increase in the temperature of the engine which results from its operation will cause a gradual decrease'in the richness of the combustible mixture supplied to the engine from the time the engine begins to operate under its own power until its temperature reaches a predetermined value when it becomes capable of operating properly upon the combustible mixture with which the carburetor Ill is designed to supply it. When the temperature of the engine reaches this predetermined value, the outer end of the bimetalllc coil spring 52 becomes disengaged from the pin 5I and, thereafter, the bimetalllc coil spring offers no resistance to the movement of the choke valve toward its open position. Because movement of the outer end of the bimetallic coil spring 52 in response to increases in temperature is not opposed by any externally applied forces, the bi metallic coil spring will not be injured even if it becomes 4heated to an excessively high temperature.

When the pressure within the intake manifold Il increases, the valve 34 will move of! its seat against the resistance of the spring 35 and gases from the intake manifold will rush thereby into Athe interior of the bellows 20 and cause it to expand. To prevent these gases carrying into the upper end of the bore 21 any particles of foreign matter which might get into and clog the small opening between the pin 3l and the bore 36 in the valve 3l, a disc 3| of tine screen wire is secured in the recess 29 in. the plug-like element 28. If the temperature of the engine is below a predetermined value, expansion of the bellows will, of course, through the linkage which connects its head 2| to the choke valve I5, cause the choke' valve to move toward its closed position. Consequently, if, when the temperature of the engine is below a predetermined value, the throttle valve I2 is moved toward its open position or the engine tends to stall, there will be a momentary increase in the richness of the combustible mixture supplied to the engine which will insure smooth and rapid acceleration or prevent stalling of the engine.

E f Since, when i within the intake manifold il rises and the belbimetallic coil spring lows 20 consequently expands and, when the ternthe free end of the perature of the engine falls;

bimetailc coil spring 52 rnpves toward the pin El, it is apparent that, whenever the engine stops, the parts of the mechanism illustrated in the drawings and hereinbeiore described automati- N'cally move to the positions in which they should be when the engine is cranked to start it.

i It may be noted that there may be associated with the mechanism illustrated in the drawings and hereinbefore described the fast idle device or thermostatic throttle stop disclosed in the Perrine application, Serial No. 618,225, filed June 20, 1932 and that the bimetallic coil spring of this device may be located in the housing for the 52 instead of in a separate housing.

Of course, although I have the mechanism to which this invention relates mounted on the intake manifold oi an engine with the bimetallic coil spring 52 located in juxtaposition to the exhaust manifold thereof, it will be understood that the mechanism may be mounted elsewhere on the engine and that the bimetallic coil spring may be located in juxtaposition to any other heated part ofl the engine.

I claim:

1. In an internal combustion engine, a carburetor, a valve for regulating the ratio oi fuel to air in the combustible mixture supplied to the engine by the carburetor, a support, a pressure actuated element mounted on the support, a shaft journaled in Ithe support and operatively conshown and described nected to the pressure actuated element, another shaft journaled in the support and operatively connected to the valve, a thermally actuated element operatively interposed between the' speciiied on 'the support for limiting moveactuatedA element, and limiting rotation of the shafts, means ment of the pressure means ongthe support for seoond-specied shaft.

2. In an internal combustion engine. a carburetor, a passage through which combustible mixture is conducted from the carburetor to the engine, a valve for regulating the richness of the combustible mixture supplied to the engine by the carburetor. a chamber with a movable wall whose movement in one direction is consonant with movement of the valve in the direction to dec'rease and whose movement in the other direction is consonant with movement of the valve in the direction to increase the richness of the combustible mixture, a thermostat through which the movable wall of the chamber is connected to the valve, a duct through which fluid may be admitted to and withdrawn from the chamber to move its movable wall connected to the chamber and the mentioned passage, and means within the duct to restrict the flow of rluid more in the direction to move the movable wall in the first- .mentioned direction than in the last-mentioned direction.

3. In an internal combustion engine, a carburetor, a passage through which combustible mixture is conducted from" the carburetor to the engine, a valveior regulating the admission of air into the carburetor,.an extensible and contractible element whose change in length in one 'direction is consonant with movement of the valve toward its open position and whose change in length in the other direction is consonant with movement of the valve toward its closed position, a thermostat through which the extensible and contractible element is connected to the valve, a duct through which duid may be admitted to and withdrawn from the extensible and contractibie element to change its length connected to the extensible and contractible element and the mentioned passage, and a valve within the duct to restrict the flow of uid more in the direction to change the length of the extensible and contractible e ment in the first-mentioned than in the second-mentioned direction;

4. In an internal retor, la passage which connects the carburetor with a cylinder of the engine, a valve for regulating the admission of air into the carburetor, a bellows whose contraction is consonant with movement of the valve toward its open position and whose extension is consonant with movement of the valve toward its closed position, a duct, through which fluid may be admitted to and withdrawn from the bellows to contract and extend it, connected to tioned passage, a valve in the duct to restrict the withdrawal of fluid from the bellows more than the admission of fluid to the bellows, and a thermally actuated element, whose movement in response to increases in temperature is consonant with movement of the ilrst-specified valve toward its open position and which may move freelyl in the direction in which it tends to move wheriits temperature rises, operatively interposed between the bellows and the first-specied Valve.

5. In'an internalA combustion engine, a carburetor, a choke valve which may bev moved toward combustion engine, a carbuthe bellows and the menpressure-responsive element and the first-mentioned passage, a valve mechanism so designed that decreases in pressure in the first-mentioned passage are sluggishly and increases in pressure in the first-mentioned passage are rapidly transmitted to the pressure-responsive element through the second-mentioned passage, and a thermostat which may move freely in the direction in which it tends to move when its temperature rises connecting the pressure responsive element to the choke valve.

6. In an internal combustion engine, a carburetor, a passage which connects the carburetor with a cylinder of the engine, a valve for regulating the richness of the combustible mixture supplied to the engine by the carburetor, a chamber with a movable wall whose movement in one direction is consonant with movement of the valve in the direction to decrease and whose movement in. the other direction is consonant with movement of the valve in the direction to increase the richness of the combustible mixture. a thermally actuated element which may move freely in the direction in which it tends to move when its temperature rises operatively interposed between the movable wall of the chamber and the valve, a duct through which fluid may be admitted to and withdrawn from the chamber to move its movable wall connected to the chamber and the mentioned passage, and means within the duct to restrict the ow of fluid more in the direction to move the movable wall in the first mentioned direction than in the last mentioned direction.

mucose 7. In an internal combustion engine, a carburetor, a choke valve in the carburetor, a passage through which combustible mixture is conducted from the carburetor to the engine, a pressure responsive element, avduct which communicates with the pressure responsive element and the passage through which combustible mixture is conducted from the carburetor to the engine, means which renders the response of the pressure responsive element sluggish to a decrease and rapid to an increase in the pressure in the passage through which combustible mixture is conducted from the carburetor to the engine, and a thermostat through which the pressure responsive element is connected to the choke valve.

8.A In an internal combustion engine, a carburetor, a valve for regulating the richness of the combustible mixture supplied to the engine by the carburetor, a pasasge through which combustible mixture is conducted from the carburetor to the engine, a pressure responsive element, a duct which communicates with the pressure responsive element and the passage through which combustible mixture is conducted from the carburetor to the engine, means which renders the response of the pressure responsive element sluggish to a decrease and rapid to an increase in the pressure in the passage through which combusti ble mixture is conducted from the carburetor to the engine, and a thermostat through which the pressure responsive element is connected to the valve.

JESSE E. ESHBAUGH. 

